made the un shell script more generic

run

@@ -1,5 +1,8 @@
 #!/bin/sh
 cd "`dirname "$0"`"
 
+result=${PWD##*/}          # to assign to a variable
+result=${result:-/}        # to correct for the case where PWD=/
+
 cd ..
-exec ./dragonruby cube-tube
+exec ./dragonruby ${result}